1. Technical Field
An apparatus is disclosed for dispensing fluids through individual nozzles mounted in a common manifold or nozzle block. The apparatus includes an improved closure system which, in a closed position, provides a cover and a seal for the nozzles to prevent dried material from clogging the nozzles. The closure system is particularly useful for dispensers of viscous, water-based fluids including, but not limited to, paint colorants.
2. Description of the Related Art
Systems for dispensing a plurality of different fluids into a container are known. For example, systems for dispensing paint base materials and colorants into a paint container are known. These paint dispensers may use twenty or more different colorants to formulate a paint mixture. Each colorant is contained in a separate canister or package and may include its own dispensing pump. Other systems for dispensing large varieties of different fluids also include systems for dispensing pharmaceutical products, hair dye formulas, cosmetics of all kinds, nail polish, etc.
Some systems for use in preparing products at a point of sale may use a stationary manifold or nozzle block through which pluralities of nozzles extend. Each fluid to be dispensed is then pumped through its own individual nozzle that is accommodated in the manifold. Depending upon the size of the container and the quantity of the fluids to be dispensed, manifolds may be designed in a space efficient manner so that a single manifold can accommodate twenty or more different nozzles. The nozzles are connected to the various fluids by flexible hoses and the ingredients are contained in stationary canisters or containers.
In many fluid dispensing applications, precision is essential as many formulations require the addition of precise or nearly exact amounts of certain ingredients. This is not only true in the pharmaceutical industry but also in the paint and cosmetic industries as the addition of more or less tint or colorant can result in a visible change in the color of the resulting product.
Precision dispensing of viscous fluids can be particularly problematic. Specifically, viscous fluids such as tints, colorants, base materials for cosmetic products, certain pharmaceutical ingredients or other viscous fluid materials have a tendency to dry and cake onto the end of the nozzles or inside the nozzle outlet openings. As a result, the nozzles may require frequent cleaning in order for the nozzles to operate accurately. The accumulation of material on or in the nozzle can cause a drop of fluid to stick to the nozzle, thereby compromising the accuracy of the dispense. While some mechanical wiping or scrapping devices are available, these devices are not practical for multiple nozzle manifold systems and the scraper or wiper element must be manually cleaned anyway. Further, cleaning of a multiple nozzle manifold can cause cross-contamination between the nozzles, which also affects accuracy of the dispense.
The drying or taking of material inside or on the nozzles is exacerbated by modern air quality requirements, which limit the use of volatile organic compounds (VOCs) as solvents. Simply put, many water-based viscous fluids dry out faster than their VOC-based counterparts. This is particularly true with paint colorants.
One solution provided in commonly assigned U.S. Pat. No. 7,261,131 is a mechanized cup-shaped closure element that covers and seals from beneath the manifold after the dispensing operation is complete. In this manner, the viscous materials being dispensed through the nozzles have less exposure to air thereby requiring a lower frequency of cleaning operations. However, while the cup-shaped closure element of U.S. Pat. No. 7,261,131 forms a sealed chamber beneath the nozzles, the amount of air in the chamber can still lead to unwanted drying and caking of material on the nozzles.